Evaluation of adequacy in empirical antibiotic therapy in a general intensive care unit

Introduction

Infectious pathologies are among the most prevalent in the ICU and significantly influence the outcome of critically ill patients. However, the emergency of resistant pathogens to different antibiotics makes the choice of the initial treatment more complex. In addition, inadequate empirical antibiotic therapy is associated with a poorer outcome.

Objectives

To evaluate the adequacy of antibiotic therapy in a general ICU and to collect data about the microbial flora in order to better adapt the empirical treatments.

Materials and methods

Data were prospectively collected in a 12-bed general ICU. The presence of infection was defined by the doctor in charge of the patient. Inadequate antibiotic therapy was defined as microbiological evidence of infection not covered by the chosen antibiotics, or by the finding of primary resistance to the antibiotics in use.

Results

Data were collected in 80 consecutive patients. The main site of infection was the lung (50%). The most prevalent microorganisms were the Gram-negative (52%). The prevalence of nosocomial infections was 60%. Empirical antibiotic therapy was inadequate in 28 episodes (35%), and the most prevalent microorganisms in this group were MRSA, Pseudomonas MR, Stenotrophomonas maltophilia. The general mortality rate was 40%, but the mortality rate among patients with inadequate antibiotic therapy was 50%, but only 33% when adequate antibiotic therapy (odds ratio = 3.09, 95% confidence interval 1.06–9.16). Risk factor to an inadequate therapy was nosocomial infection (relative risk 2.07, 95% confidence interval 1.01–4.26). Other risk factors that showed a non-significant trend were a delay to starting antibiotics greater than 24 hours, immunosupression, septic shock and higher APACHE II score. The number of empirical treatment schemes was 17.

Conclusion

These preliminary data showed that there is an excess in mortality rate when empirical therapy is inadequate. The inadequacy of treatment was associated with nosocomial infections. There was an exaggerated variability on the choice of empirical strategy.